Thermally threated safety glass
To improve the security aspects of glass (either float glass, figure glass or coated glass) this standard glass undergoes a thermal treatment. As a result of a thermal treatment the glass becomes stronger, but not harder as some names do suspect.
Also glass that is used at isolating glazing or laminated security glass can be thermally treated. The ennoblement process of basic glass results, depending on the method, in two thermal glass alternatives:
- Thermally pre-stressed glass
- Thermally reinforces glass
These are the official names for reinforced glass. In practice however they are frequently called differently:
- Thermally pre-stressed glass we also know as hardened glass, pre-stressed glass and full tempered.
- Thermally reinforced glass we also know as half hardened glass, half pre-stressed glass, and durci
Specific characteristics of thermally pre-stressed or hardened glass
- The shock loading is up to 4 or 5 times larger than of basic (float) glass.
- The fatigue resistance is up to 4 or 5 times larger than of basic (float) glass.
- Temperature shocks (temperature differences in one window) up to 200ºC can be caught. At basic (float) glass only temperature differences up to approximately 30ºC are feasible.
- Thermally pre-stressed or hardened glass breaks in small, not-cutting glass grains. This reduces the risk for personal injury considerably. Because of this hardened glass has the title security glass, which is conform NEN 3569.
Thermally pre-stressed or hardened glass is among others applied for isolating glazing, laminated security glass, doors, front glazing, entries, frontages, moving staircase, lift shafts, bathroom elements and as glass for furniture applications.
Specific characteristics of thermally reinforced or half hardened glass:
- The shock loading is up to 2 or 3 times larger than of basic (float) glass.
- The fatigue resistance is up to 2 or 3 times larger than of basic (float) glass.
- Temperature shocks (temperature differences in one window) up to approximately 100ºC can be caught. At basic (float) glass only temperature differences up to approximately 30ºC are feasible.
- Thermally reinforced glass has the same breaking pattern as basic (float) glass. Because this glass therefore has the risk of wounds thermally reinforced glass belongs not to the security glass at all.
- Thermally hardened glass has a better optical quality than thermally pre-stressed or hardened glass by reduction of the optical distortion which are inherent to the temperatures and the length of time of the hardening process.
- A another advantage with regard to thermally pre-stressed glass can be that at a break not the whole window is falling, but that (large) fragments, just like at basic (float) glass, stays at their place.
- At thermally reinforced glass is no Heat Soak Tests necessary, which is carried out for reducing spontaneous breaking by a nickel-sulphide-containment.
Thermally reinforced glass is particularly used to prevent a breaking as a result of large temperature differences in the glass element, for example as a result of cast shadow. Scopes are among other things front glazing, both as look through and at breast.
Security glass can be combined with numerous other applications to improve the comfort of living, such as the self-cleaning functioning, a better thermal heat insulation, protection of goods, acoustic isolation and decoration.